1. Field of the Invention
This invention relates to loading workpieces supplied by a transport device to a designated pick-up site for presentation to a processing device such as a decorating facility. More particularly the present invention relates to an apparatus wherein a workpiece such as a glass vessel is manipulated from a supply conveyor with an initial lifting motion out of supporting contact therewith and concluding with delivery motion to the carrier in which the workpiece has been reorientated for disposition o the carrier suitable for carrying-out the processing operation, such as decorating.
2. Description of the Prior Art
As shown in U.S. Pat. Nos. 2,231,535; 2,261,255; 2,721,516; and 3,146,705 intermittent motion type decorating machines are known in the art and provide a drive system to impart intermittent traveling motion to the workpieces such as containers made of glass or plastic. A container is moved through a predetermined distance, stopped, moved again through a predetermined distance, stopped and again moved until each container through the sequence of motions moves completely through the decorating machine. A decorating station will be provided at each place where the container comes to a stop. At the decorating station a decorating screen is displaced into line contact with the surface of the container by an associate squeegee and then the container is rotated and the squeegee remains stationary for a decorating process. It is advantageous for this decorating process to provide that the container surface which is to receive the decoration is horizontally oriented. This is because the printing medium is subject to the influence of gravity whereby the printing medium can be uniformly spread across the screen surface when the squeegee moves horizontal. When the squeegee surface, for example, is orientated vertically, the ink or other printing medium is difficult to maintain uniformly throughout the height of the printing screen. The advantages of decorating the workpiece while the workpiece is orientated horizontally is equally applicable to other examples of workpieces such as glass tumblers where, for example, it is possible to grip the workpiece at one end only. With respect to a soda bottle, for example, the bottle mouth, forming the support site, is too small to sustain the weight of the bottle by a vacuum chuck. Therefore, it is necessary to engage opposite ends of the soda bottle for adequate support.
There are, however, machines known in the art for applying decoration to a surface while orientated vertically. An example of such a machine is disclosed in U.S. Pat. No. 4,463,371. The present invention seeks to provide a workpiece load device that can supply workpieces at spaced apart time intervals in a reliable fashion to a support structure used to bring a workpiece to a decorating station. In this regard, it is necessary to provide a manipulative structure suitable to receive a supply of workpieces from one conveyance structure and present these workpieces in succession to a second support structure in which the manner of support, when desired, can be diversed. For example, workpieces can be presented to the feed device with the surface to receive the decoration orientated vertically and transposed by the feed device to a horizontal orientation. This is a typical and most desirable manner for handling containers since the container occupies a minimum space when supported to extend vertically and then reorientated for the decorating process to extend horizontally. It is, however, within the scope of the present invention to receive workpieces with the workpiece surface to receive decoration orientated horizontally and to maintain that horizontal disposition throughout the loading and decorating processes for the workpiece. Similarly, workpieces having a decorative receiving surface orientated vertical may remain vertical while manipulated by the loading operation whereby the vertical orientation remains during a printing process such as shown in U.S. Pat. No. 4,463,671.
Certain workpieces because of their configuration and material of construction, such as glass tumblers which are tall truncated cones with a bottom, must be moved with great precision from a supply conveyor to a carrier in a decorating machine. Ever changing variables from glass tumbler to a glass tumbler include surface irregularities at the touch sites where the glass tumbler will be supported by the gripping members used to load the workpiece. Also the glass tumbler should move along a path of travel that avoids the possibility of impact with the conveyor structure used to supply the tumbler to the feeding mechanism. Impact must also be avoided with a retention device used to hold the tumbler throughout the decorating process. The avoidance of impact is particularly acute to satisfy necessary operating speeds to achieve an acceptable through-put capacity for the decorating machine. Operator fatigue precludes use of workers to feed workpieces, such as glass tumblers, to a decorating machine. Moreover, in a decorating machine using silk-screen printing techniques, after the screens are provided with an ink supply, the printing operations should proceed without extended periods of interruption. Printing delays due to down time of allied equipment allow an unwanted dispersement of printing medium through the silk-screen without extraction of the printing medium from screen by a workpiece. The matter is particularly acute when, for example, multiple colors are printed using multiple printing stations. When four different colors are being printed in a single decorating machine, each of the four different printing stations for the various colors must be subject to a clean-up operation before the decorating machine can be placed back on a production basis. Restarting the printing operation after a delay requires cleaning smeared printing from workpieces which is very labor intensive.